You should run into a chest that contains the stone armor. Cross the bride and then head immediately left and follow the building wall back around to where the bridge is. After that just follow the cliff on the left until you reach a bridge. There are five humanoid mobs to take care of which you can do normally or you can glitch them into running off of a cliff by standing on the ledge to the left of the stairs that you go down after going through the crest door. If you go through the crest door be sure the break the wall and checkpoint at the bonfire because most of the enemies in this area will kill you in a single hit. The enemies here will likely kill you though so I would really recommend just helping people kill the capra demon a couple of times to get the 20k souls for the crest from the blacksmith in the undead parish
If you managed to kill the hydra you can take a ladder up by the large waterfall and then get into the back of the garden that way without having to buy the key for the crest door. You will need to either be able to get past the crest door in the darkmoon garden or you can get into the same area by taking a back entrance where the hydra is in the darkmoon basin. You can get a set of stone armor from a chest that is far better than the eastern armor and elite knight armor (as well as the gold-hemmed black armor).
